One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,5)(4,6)(7,8)(9,10)(11,18,21,15)(12,16)(13,22)(14,17)(19,24,20,23)(25,26,29,32,30,33,28,37)(27,34,36,39,35,31,38,40)(2,5)(3,8)(6,7)(9,11)(10,15)(12,19)(13,20)(14,21)(16,23)(17,18)(22,24)(25,27)(26,31)(28,36)(29,38)(30,35)(32,39)(33,34)(37,40) involution — undirected(2,6)(5,7)(9,12,14,13)(10,16,17,22)(11,19,21,20)(15,23,18,24)(27,35)(31,34)(36,38)(39,40)(2,6)(5,7)(9,13,14,12)(10,16,17,22)(11,20,21,19)(15,23,18,24)(25,28,30,29)(26,32,33,37)(27,36,35,38)(31,39,34,40)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.